5 Things to Know About Phosphate Testing for Algae

Test for phosphates only if you have a stubborn algae problem and standard treatments aren’t working. Otherwise, skip it entirely.

Phosphates are plant food that feed algae, even when your chlorine or other sanitizers are perfect. High levels make algae control much harder.

Testing is simple and cheap—use a drop kit or test strips, just like pH or nitrate tests. It takes two minutes and one bottle lasts years.

Knocking down phosphates makes algae control much easier. Without testing, you’re guessing and wasting algaecide when removing their food source is the real fix.

In pools, use phosphate removers. In aquariums, water changes and plants handle it. Don’t test if your water is clear and algae-free—phosphates aren’t your problem then.